Parallax compensation camera light

ABSTRACT

A light for a camera having an objective lens coupled to an automatic focusing apparatus. A link assembly connects the focusing apparatus to a pivotally supported camera light reflector. The position of the reflector is varied in accordance with the setting of the focusing apparatus so as to direct the light beam at the subject over a wide range of subject to camera distances.

United States Patent [191 Hartmann 1 Jan. 1, 1974 [54] PARALLAXCOMPENSATION CAMERA 2,585,653 2/1952 Heehler 240 441 x LIGHT I V3,280,320 10/1966 Beaton et a1 i 3,296,947 l/1967 Engelsmann et al 95/1R Inventorl Rudolf Hartman", SkOkIe. 3,584,559, 6/1971 Levin 352 140 x[73] Assignee: Bell & Howell Company, Chicago,

Primary Examiner-Fred L. Braun [22] Filed Nov 1 1972 AttorneyWilliam K.Serp et al.

[21] Appl. No.: 302,682

' 57 ABSTRACT [52] g 'g A light for a camera having an objective lenscoupled {51] I t Cl G63) 15/02 to an automatic focusing apparatus. Alink assembly [58] 3 2 C 20 connects the focusing apparatus to apivotally supz j'gk'i'fi'" ll ported camera light reflector. Theposition of the re- 140 flector is varied in accordance with the settingof the focusing apparatus so as to direct the light beam at the subjectover a wide range of subject to camera dis- [56] References Citedtancesi UNlTED STATES PATENTS 3,369,467 2/1968 Land 95/11 L 7 Claims, 2Drawing Figures This invention generally relates to a light for a cameraand more particularly relates to a light for a camera including anobjectivelens having an adjustable focus wherein the light isautomatically directed at the subject over a wide range of subject tocamera distances.

Presently available motion picture cameras such as super 8mm camerasusually include means for automatically focusing the lens. One suchfocusing arrangement is described in U. S. Pat. application Ser. No.147,943, filed May 28, 1971, now US. Pat. No. 3,715,161, by Henry J.Koeber entitled, Lens Focusing Mechanism With Manual Control and havinga common assignee withthis application. The device described in thisreference utilizes the triangulation method of len focusing. The lengthof the vertical side of the triangle is empirically determined as theheight of an average adult above the supporting plane on which the userstands. The user aligns the base of a remote subject with a referencemark in the viewfinder thus angling the camera by a determined amount.When the optical axis of the cameras lens is tilted with respect to thehorizontal at the given angle to both the vertical side and the baseside of the triangle, the required values necessary to compute theunknown length of the base line are available. As described in thisreference, the user sights at the base of the subject and depresses afocusing lever conveniently located upon the camera. The lens thenautomatically focuses at the desireddistance and the lever is releasedto lock the focus setting.

Present movie lights generally include a lamp mounted in relation to aparabolic reflector, the lamp being mounted by suitable means on top ofthe camera. The primary axis of the reflector is generally fixed inrelation to the axis of the lens.- To provide the greatest amount oflight at distance subjects, the axis of the reflector is set duringmanufacture to intersect the lens axis at the maximum subject distanceat which the light will provide sufficient illumination. For generaluse, this setting provides an acceptable compromise; however, at shorterfilming distances, the light isdirected beyond rather'than at thesubject. It will be appreciated that this arrangement, being acompromise, results in inefficient use of the movie light.

In an effort to eliminate this parallex condition, the housing ofcertain movie lights is swiveled with respect to the camera so that theuser may manually direct the light toward the subject beingphotographed. Thus, the housing position is adjusted for each filming sothat the primary axis of the light beam will intersect the subject. Aparticular inconvenience with such an arrangement is that the user mustadjust the light housing for each selected lens focus setting.Frequently, due to pressures of' time, the user may forget to correctthe adjustment resulting in a light concentration which is considerablyless than optimum A main object of this invention is to provide a lighthaving an adjustable axis of illumination the position of whichautomatically corresponds to the prevailing subject to camera distance.

Other objects and advantages of this invention will become apparent fromthe following description and drawings, in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a preferredembodiment of a light and cooperating camera including certain featuresof this invention with the camera fragmentarily and the lightsectionally illustrated.

FIG. 2 is a sectional view of the light along the line 22 of FIG. 1.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Although the illustratedembodiment is hereinafter described with respect to a motion picturecamera it will be appreciated that the features of this invention may beutilized with other optical devices.

Briefly, as illustrated in FIG. 1, the embodiment comprises a motionpicture camera 10 having an objective lens 12 defining a lens axis 13and means 15 for adjusting the focus setting of the lens so as to permitfocusing at various subject to camera distances. Mounted to the top ofthe camera 10 is a movie light 14 including means for varying theprimary axis of the light'beam so that it may be directed at'theselected subject over a wide range of subject to camera distances. Aswill be subsequently described, means are included for varying thedirection of the light beam as determined by the focus setting of thelens 12. 1

The movie light 14 includes a light housing 16 which defines an opencavity wherein a light source in.the form of a bulb 18 is supported. Thehousing includes a rear wall 20 and the periphery of the'openingof thehousing is formed to define a continuous channel 22 for receiving aprotective transparent cover 24. Within the cavity of the lighthousingl6 and mounted for rotational movement with respect thereto is aparabolically shaped reflector 26 having a primary axis 27. Thereflector 26 is formed of thin gauge polished metal. As particularlyillustrated in FIG. 2 the periphery of the reflector is stampedto'define opposing bosses 28 and 30 which receive dimples 32 and 34formed in the inner wall of the light housing 16. During assembly, themetalic reflector 26, due to its resilient characteristic, is snappedinto the housing so that the bosses 28 and 30 arein registration withthedimples 32 and 34 thereby permitting rotational movement of thereflector 26 with respect to the housing 16. The axis of rotation of thereflector 26 is through its diameter and normal to a plane passingthrough the axis 13 of the camera lens 12 and the center of thereflector 26. The reflector 26 defines a circular opening 36 throughwhich passes a lamp support rod 38 one end of which is secured to therear'wall 20 of the housing 16 by means of a suitable fastener such asscrew 40. To the remaining end of the lamp support rod 38 is secured alamp socket 42 for receiving the lamp 18. Thus, the lamp 18 is fixed inrelation to the light housing 16 wherein the parabolic reflector 26 isrotatably mounted. By rotating the reflector 26 about its rotationalaxis, the point of intersection of the primary axis 27 of the reflectorand the lens axis 13 can be varied to correspond with the distance tothe subject from the camera 10 as will hereinafter be further described.

Secured to the reflector 26 adjacent the circular opening 36 is areflector positioning lug 44 which defines an elongated slot 45 forreceiving a reflector drive shaft 46. The reflector drive shaft 46passes through a light support pedestal 48 and into the camera 10. The

camera includes a housing 50 and projecting from a front wall 52 of thehousing is the lens 12. Enclosed within the housing 50 is a focusingmechanism (not shown) for adjusting the focus of the lens to correspondwith the subject to camera distance. A suitable focusing mechanism isdescribed in the aforecited U. S. Pat. application Ser. No. 147,943.

The focus setting of the lens is set in response to a manual operation.A manually engagable release member 54 is depressed while the camera 10is angled at the base of the subject. In this condition the focusingmechanism automatically sets the camera focus to the desired setting andthe member 54 is released locking the lens 12 at the desired focussetting. As the member 54 is released it moves in a counter-clockwisedirection toward its initial position; however, the return movement islimited so that the release member 54 returns to a position with respectto the camera which corresponds to the focus setting'of the lens 12. Inthis position, both the lens 12 and the release member '54 are locked inposition. As illustrated in FIG. 1, the release member 54 is shown inits fully released, clockwise position which corresponds to an infinitefocus setting of the lens 12. In response to a relatively close focus,the release member 54 will lock in a counter-clockwise directionattaining the position illustrated by the phantorn lines in FIG. 1. Thefocusing distance is indicated on the face of a suitably scaled meter 56across which rides an indicating pointer 58. The release member 54 ispivotally supported to the camera body 50 by means of a pivot screw 60and includes an extension arm 62. The end of the extension arm 62defines slot 64 serving to receive the reflector drive shaft 46.

For purposes of discussion it will be assumed that the camea 10 isinitially in the position illustrated in FIG. 1 with the lens focused atinfinity and the axis 27 of the reflector 46 substantially parallel tothe axis 13 of the objective lens 12. The user then sights the objectivelens at the base of the subject to be photographed and depresses theoperating lever 54 in a completely counter-clockwise direction asindicated by an arrow 66. The pointer 58 will arrive at, for example,the phantom position indicating a four foot distance from the camera tothe subject. The user then releases the operating lever 54. Theoperating lever 54 will then move in a counter-clockwise direction;however, it will lock at the phantom position illustrated and thepointer 58 will similarly lock indicating the position at which thefocusing mechanism of the camera is set. The user then directs thecamera 10 at the subject upon which the setting has been made andproceeds with the filming operation. It will be noted that the arm 62and the operating 1 lever 54 arenow in the position illustrated inphantom forcing the reflector positioning lug 44 upwardly to its phantomposition. In this manner, the reflector 26 is turned on its rotationalaxis to the phantom position thereby directing the light beam downwardlytoward the subject being photographed. As described, the position of thereflector 26 is adjusted to correspond with the focus setting of thelens 12 so that the primary axis 27 of the reflector 26 will intersectthe axis 13 of the objective lens 12 substantially at the subject.

While this invention has been particularly shown and described with thepreferred embodiment, it will be understood that various changes in formand detail may be made without departing from the spirit and scope ofthe invention as set forth in the following claims.

I claim:

1. In combination with an optical device having an adjustable focus lenshaving a primary axis, means for adjusting the focus of the lens, and alight for illuminating the subject being photographed including areflector having a primary axis and a light source, the improvementcomprising means mechanically coupling said reflector to the lens focusadjusting means so that the point of intersection of the primary axis ofthe reflector and the primary axis of the lens is varied as a functionof the focus setting of the lens.

2. The combination of claim 1 wherein said reflector is pivotallymounted about an axis normal to a plane passing through the primary axesof the lens and the reflector so that said coupling means serves to varythe angular orientation of the primary axis of the reflector withrespect to the axis of the lens in accordance with the focus setting ofthe lens.

3. The combinationof claim 1 wherein said coupling means includes a linkassembly operatively associated between said reflector and said lensfocus adjusting means, and said lensfocus adjusting means includes amanually operable member which attains a position related to the focussetting of the lens, said link assembly being coupled to said manuallyoperable member and to said reflector for positioning thereof. 7

4. In combination with an optical device having an adjustable focus lenshaving a primary axis, means for adjusting the focus of the lens, and alight for illuminating the subject being photographed, the lightincluding a reflector having a primary axis and a light source, saidreflector being movable with respect to the lens, the improvementcomprising: means coupling said light to the lens focus adjusting meansso as to vary the point of intersection between the light beam from thelight and the axis of the lens, said coupling means serving to vary theprimary axis of the reflector with respect to the axis of the lens inaccordance with the focus setting of the lens, said coupling meansincluding a link assembly one end of which is coupled to said reflectorand the remaining end of which is connected to the lens focus adjustingmeans.

5. The apparatus of claim 4 wherein said reflector is rotatable withrespect to the lens about a fixed axis, said fixed axis being normal toa plane passing through the center of said reflector and the camera lensaxis so as to facilitate adjustment of the point of intersection betweenthe primary axisof the reflector and the axis of the lens.

6. The apparatus of claim 5 wherein the lens focusing means includes amanually operable member which attains a position related to the focussetting of the lens, said link assembly being coupled to said manuallyoperable member and to said reflector for positioning thereof.

7. The apparatus of claim 6 wherein said link assembly includes a lugsecured to said reflector and an elongated drive rod coupled to said lugand passing into the camera body, the remaining end of said drive rodbeing coupled to said manually operable member for movement therewith.

t a a

1. In combination with an optical device having an adjustable focus lenshaving a primary axis, means for adjusting the focus of the lens, and alight for illuminating the subject being photographed including areflector having a primary axis and a light source, the improvementcomprising means mechanically coupling said reflector to the lens focusadjusting means so that the point of intersection of the primary axis ofthe reflector and the primary axis of the lens is varied as a functionof the focus setting of the lens.
 2. The combination of claim 1 whereinsaid reflector is pivotally mounted about an axIs normal to a planepassing through the primary axes of the lens and the reflector so thatsaid coupling means serves to vary the angular orientation of theprimary axis of the reflector with respect to the axis of the lens inaccordance with the focus setting of the lens.
 3. The combination ofclaim 1 wherein said coupling means includes a link assembly operativelyassociated between said reflector and said lens focus adjusting means,and said lens focus adjusting means includes a manually operable memberwhich attains a position related to the focus setting of the lens, saidlink assembly being coupled to said manually operable member and to saidreflector for positioning thereof.
 4. In combination with an opticaldevice having an adjustable focus lens having a primary axis, means foradjusting the focus of the lens, and a light for illuminating thesubject being photographed, the light including a reflector having aprimary axis and a light source, said reflector being movable withrespect to the lens, the improvement comprising: means coupling saidlight to the lens focus adjusting means so as to vary the point ofintersection between the light beam from the light and the axis of thelens, said coupling means serving to vary the primary axis of thereflector with respect to the axis of the lens in accordance with thefocus setting of the lens, said coupling means including a link assemblyone end of which is coupled to said reflector and the remaining end ofwhich is connected to the lens focus adjusting means.
 5. The apparatusof claim 4 wherein said reflector is rotatable with respect to the lensabout a fixed axis, said fixed axis being normal to a plane passingthrough the center of said reflector and the camera lens axis so as tofacilitate adjustment of the point of intersection between the primaryaxis of the reflector and the axis of the lens.
 6. The apparatus ofclaim 5 wherein the lens focusing means includes a manually operablemember which attains a position related to the focus setting of thelens, said link assembly being coupled to said manually operable memberand to said reflector for positioning thereof.
 7. The apparatus of claim6 wherein said link assembly includes a lug secured to said reflectorand an elongated drive rod coupled to said lug and passing into thecamera body, the remaining end of said drive rod being coupled to saidmanually operable member for movement therewith.